Sarepta Asks FDA to Approve Gene Therapy SRP-9001 for DMD

Gene therapy would be the first available for patients with Duchenne muscular dystrophy

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Sarepta Therapeutics has submitted an application to the U.S. Food and Drug Administration (FDA) asking the agency to grant accelerated approval to the gene therapy SRP-9001 (delandistrogene moxeparvovec) as a treatment for Duchenne muscular dystrophy (DMD) in patients who are able to walk.

“Every hour of every day, this ruthless disease, Duchenne, robs thousands of children in the United States of muscle as it steals their future from them. Sarepta’s BLA [biologics license application] submission for an accelerated approval of SRP-9001 is a significant milestone in our quest to intervene with urgency on behalf of the children we serve,” Doug Ingram, president and CEO of Sarepta, said in a press release.

DMD is caused by mutations in the gene that provides instructions for making dystrophin, a protein that helps to protect muscle cells from damage. SRP-9001 is designed to deliver a gene encoding micro-dystrophin (a shortened but functional version of the dystrophin protein) to the body’s muscle cells using a viral vector. The therapy is being co-developed by Sarepta and Roche.

“If approved, SRP-9001 will be the first gene therapy available for Duchenne patients,” Ingram said.

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The companies have asked the FDA to grant SRP-9001 accelerated approval. This is a pathway the FDA uses to permit companies to sell medications based on early clinical data showing the treatment is likely effective, while requiring the therapy’s sponsors to conduct additional testing to prove efficacy.

In this case, Sarepta’s application is supported by trial data showing SRP-9001 treatment can induce expression of the micro-dystrophin protein. According to the company, production of functional dystrophin is reasonably likely to predict clinical benefit in people with DMD.

The application is supported by data from a proof-of-concept Phase 1/2 clinical trial called Study 101 (NCT03375164), which demonstrated that a single dose of SRP-9001 could improve walking abilities after three years in four boys with DMD.

The application also is supported by data from the Phase 2 trial Study 102 (NCT03769116), which similarly showed the treatment improved motor function in 41 boys with DMD, and by data from an open-label Phase 1 study called ENDEAVOR (NCT04626674).

“We are enormously grateful to the courageous families who have participated in the SRP-9001 trials and to the participating clinical investigators and experts who have guided us and played a crucial part in reaching this milestone,” Ingram said.

Sarepta is sponsoring a Phase 3 trial called EMBARK (NCT05096221), which is testing SRP-9001 against a placebo in more than 100 boys with DMD with the main aim of comparing the effect on motor function after one year. Sarepta has proposed that, if the FDA decides to grant SRP-9001 accelerated approval, data from EMBARK could serve as proof of efficacy to support a full approval later.

The FDA has previously granted SRP-9001 fast track, orphan drug, and rare pediatric disease designations.